Keeping Your Cool: Testicular Temperature and Sperm Health

There’s a biological reason the testicles hang outside the body: sperm production works best at a temperature cooler than core body temperature.

The testes have their own sophisticated temperature-regulation system, and research has consistently shown that excessive testicular heat can negatively affect sperm production and semen quality. Studies have examined heat exposure from sources ranging from hot environments and prolonged sitting to saunas and other lifestyle factors.

That has led to growing interest in the opposite question: could keeping the testicles cooler support sperm health?

The idea isn’t new. Researchers have studied scrotal cooling for decades. Some small studies have reported improvements in semen parameters, including sperm motility, following periods of scrotal cooling. More recently, researchers studying men with abnormal semen parameters reported increases in average sperm motility and vitality after the use of cooling devices.

But there’s an important distinction between interesting science and established medical advice. A systematic review of the research found encouraging signals but concluded that there was not yet enough high-quality evidence to say definitively that scrotal cooling improves male fertility.

So, what do we know?

Temperature matters. The testes are naturally designed to operate cooler than the rest of the body, and excessive heat can interfere with normal sperm production.

Whether actively cooling the testicles can meaningfully improve sperm motility or fertility remains an intriguing area of research.

Sometimes, when it comes to sperm health, keeping your cool may be more than just an expression.